Find the equation of the line for which

Given: $p=4$ and $\alpha=1800$

Here $p$ is the perpendicular that makes an angle $\propto$ with positive direction of $x$-axis, hence the equation of the straight line is given by:

Formula used:

$x \cos \propto+y \sin \propto=p$

$x \cos 1800+y \sin 1800=4$

i.e; $\cos 1800=\cos (5 \times 360)=\cos (5 \times 2 \pi)=\cos 360=1$

similarly, $\sin 1800=\sin (5 \times 360)=\sin (5 \times 2 \pi)=\sin 360=0$

hence, $x \times 1+y \times 0=4$

Hence The required equation of the line is $x=4$.